Dissipation in circuit quantum electrodynamics: lasing and cooling of a low-frequency oscillator

Julian Hauss, Arkady Fedorov, Stephan André, Valentina Brosco, Carsten Hutter, Robin Kothari, Sunil Yeshwant, Alexander Shnirman, Gerd Schön

Published 2008-06-08Version 1

Superconducting qubits coupled to electric or nanomechanical resonators display effects previously studied in quantum electrodynamics (QED) and extensions thereof. Here we study a driven qubit coupled to a low-frequency tank circuit with particular emphasis on the role of dissipation. When the qubit is driven to perform Rabi oscillations, with Rabi frequency in resonance with the oscillator, the latter can be driven far from equilibrium. Blue detuned driving leads to a population inversion in the qubit and lasing behavior of the oscillator ("single-atom laser"). For red detuning the qubit cools the oscillator. This behavior persists at the symmetry point where the qubit-oscillator coupling is quadratic and decoherence effects are minimized. Here the system realizes a "single-atom-two-photon laser".